Quote from GashnawI would MUCH rather see Rofellos as a general or Primeval titan hit the board than Omniscience.
Are you trolling?
Quote from ChampBlankmanI have an elf tribal deck that can generate silly amounts of mana and Gen Wave is one of my favorite things to cast with it. Most of this is because I run a majority of creatures and other permanents, so I don't often miss with it.
That being said, I have seen it cast and whiff miserably, which is really annoying if it ends up binning a lot of good spells, since in green it's somewhat difficult to get back stuff from the yard.
Quote from WingedkagoutiYou can only play the cards if they would somehow be legal to play.
If a spell in a graveyard has flashback, you can cast it. If a card in a graveyard specifically lets you play it from the graveyard (such as Haakon, Stromgald Scourge), you may play it. If you have Haakon in play, you may play Knights from your opponents' graveyards.
If it's your turn during the main phase and you have Crucible of Worlds in play, you may play a land from an opponent's graveyard, if you haven't already played all the lands you could this turn.
As far as I can tell, Chandra Ablaze's ultimate should let you cast Red instants/sorceries from your opponents' graveyards.
Past in Flames only grants the cards in your own graveyard flashback, so you won't be able to use Trance to cast cards from your opponents' graveyards with this.
You can not activate a Reassembling Skeleton or creatures with Unearth. Nor can you activate something like Magma Phoenix. Your opponents will still be able to use these abilities.